“Good Cholesterol” A Myth?

New study casts doubt on the role of HDL

While most of us might not be able to define HDL cholesterol, we usually do know it’s the good kind. Why? For years, doctors and scientists have dubbed high-density lipoprotein (HDL) the “good cholesterol” due to the belief that HDL—a type of lipoprotein that helps transport cholesterol and triglycerides in the blood—helps lower the risk of heart disease. That belief is so strong that many doctors prescribe drugs like niacin to help raise HDL levels—even when all heart disease risk factors fall within healthy ranges. But a new study threatens to turn that thinking on its head.

Roughly 100 doctors and medical professionals from dozens of health institutions participated in the Lancet study, which examined the genetic profiles and heart-disease outcomes of more than 100,000 people. The researchers focused on people who carry specific genes that cause an increase in their production of HDL.

[sidebar]The thinking was: If so-called “good cholesterol” is directly responsible for improving cardiovascular health, then higher HDL levels should result in healthier hearts. But that’s not what they found. People who carried the high-HDL genes were shown to suffer the same rates of heart disease as those with lower HDL levels.

So what does this mean? Nothing yet, says Steven Nissen, MD, Prevention advisor and chairman of cardiovascular medicine at the Cleveland Clinic. “This new research is interesting but not definitive,” he says. “People with high levels of HDL have a lower incidence of coronary heart disease. We’ve known that for decades.” What’s less clear, he says, is whether HDL is the cause of the drop in heart disease risk or simply a byproduct of other proven heart-strengtheners like diet and exercise.

Dr. Nissen, who is working with the pharmaceutical company Lilly to test an HDL-boosting drug, says the Lancet study examines the genetic side of HDL, but not the environmental side. “There are many different forms of HDL, and I still don’t think we have a complete picture of HDL’s potential benefits,” he says.

Until science has a more complete understanding of HDL, Dr. Nissen recommends all those taking measures to boost HDL levels continue to follow their doctor’s instructions.